New barrier to keep blood-sucking parasite under control?

Michigan is taking ownership of a dam on the Manistique River in the Upper Peninsula.

That will allow the federal government to build a new barrier there to keep sea lampreys from breeding in the river. Managers of the fishery expect that will bring the lamprey problem under control in Lake Michigan.

For more than fifty years Canada and the U.S. have been battling the eel-like creature across the Great Lakes. Sea lampreys are parasites that drill holes in fish to feed on blood and body fluids. They often kill the fish. The sea lamprey was one of the first invasive species to arrive in the lakes, and it’s the only invasive to be successfully controlled by humans.

The Manistique is one of the largest watersheds in the Upper Great Lakes. Wildlife officials were caught off guard about a decade ago when it was discovered sea lamprey were passing an old dam near the river mouth and spawning upstream. That was one reason the lamprey population in Lake Michigan surged around 2007.

And today, sea lampreys are still more numerous than fisheries biologists would like. Lamprey keep lake trout from recovering and also attach to white fish and salmon. The U.S. Army Corps of Engineers is ready to build a new barrier on the Manistique River and Michigan’s willingness to own the dam could allow that to happen by 2014.

For fifty years Canada and the U.S. have been battling an eel-like creature across the Great Lakes. Sea lampreys are parasites that drill holes in fish to feed on blood and body fluids. They often kill the fish. The sea lamprey was one of the first invasive species to arrive in the lakes, and it’s the only invasive to be successfully controlled by humans.

But in recent years, the lamprey has been getting the upper hand in the struggle. As Peter Payette reports there might be more setbacks in the near future:

If you’re on a lamprey control team you get to see all the prettiest streams and rivers in the Great Lakes. That’s because lampreys like clean water.

“Part of our problems recently have been some of the streams that were too dirty to harbor lampreys have been cleaned up and now we have lampreys in parts of the Saginaw River. We never had lampreys in that up until 15 or 20 years ago.”

Ellie Koon supervises one of the U.S. Fish and Wildlife treatment teams. They spend the warm months killing young lampreys by the thousands.

They treat rivers using a chemical called lampricide. It’s a poison that rarely hurts other fish. In fact, during a treatment the fish get a feast they normally wouldn’t. Young lampreys look a bit like worms at this stage and stay in the mud. But when they’re poisoned they swim out where fish can grab them.

Ellie Koon and one of her team members, Hank Cupp, say fish and other animals in the river pig out.

“You can almost hear the fish burping the day after we treat. You can see them swimming around with lampreys hanging out of their mouths that they can’t swallow.”

Sea lampreys are invasive parasites found in every one of the Great Lakes. It’s a fish with a round mouth like a suction cup. It latches onto big fish like trout and salmon... and kills them by drinking their blood.

It costs fisheries managers in the U.S. and Canada 20 million dollars a year to control the lamprey.

There’s one secret weapon in development that could eventually save them money... pheromones. Those are odors that male lampreys release to attract the lady lampreys.

"Pheromones are typically species specific, so they should have minimal impact to other species, they're highly potent, effective at very low concentrations. So once they're developed they could be applied relatively cheaply and with little environmental impact."